All solutions here are SUGGESTED. Mr. Teng will hold no liability for any errors. Comments are entirely personal opinions.

(a)
(i)

(ii)

(b)
(i)
Model A: $r = -0.9470$
Model B: $r= -0.9749$

(ii) Since the $|r|$ is close to 1 for Model B, Model B is the better model.
$P = -33659.72 \mathrm{ln}m + 195693.559$
$P \approx -33700 \mathrm{ln}m + 196000$ (3 S.F.)

(iii) Required estimated price $= -33659.72 \mathrm{ln}(50) + 195693.559 = \64000$